Digital still cameras are used to take photographs which are usually rectangular, with the dimensions of the rectangle being defined by a long axis and a short axis. The user of a digital still camera (DSC) can operate the camera at any orientation. However, most photographs are taken either in a landscape orientation, where the long axis of a photograph is horizontal, or in a portrait orientation, where the long axis of a photograph is vertical.
Photographs that are taken are subsequently displayed on a display device such as a computer, which will usually present the photographs in a landscape orientation. Thus, any photographs that have been taken in the portrait orientation have to be rotated to be viewed in the correct orientation. This is time-consuming and annoying for a user of the camera and/or the display device.
Some cameras incorporate a mechanical device for measuring the orientation of the camera, such as a mercury or ball based tilt switch. However, these are physically large, which is a major disadvantage for incorporation in a modern DSC, and there are also environmental concerns with the use of mercury.